Hello. I've noticed several athletes that I train with put 2.5lb metal plates under their heels whenever they do squats (back, front, and overhead). I know they do this to increase their depth while still keeping their heels down. I know in my gut that this isn't a good idea and they should develop the mobility required to squat without them but I'm not smart enough or eloquent enough to explain it to them. How do I explain that this is not an effective strategy and how do I explain how to develop the capability to squat without relying on these little plates? Thank you.